How to use tapply with more than one variables grouped

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of noobmin
Sent: Monday, October 22, 2012 2:28 AM
To: r-help at r-project.org
Subject: [R] How to use tapply with more than one variables grouped

I'm studying alone the R language for data preparation. I found a
course at MIT for data preparation that uses python but I'm using R to
learning. The first exercise is the preparation of data from a database
that shows the contributions made to candidates for U.S. president. The
database is described in FORMART
ftp://ftp.fec.gov/FEC/Presidential_Map/2012/DATA_DICTIONARIES/CONTRIBUT
OR_FORMAT.txt
link. I wonder how to print the table showing how many states are
President Obama the top candidate (by full amount of donations
received) with R language?

I try using tapply method but, i dont understand how to working with
more than one variable grouped. Could anyone help me in advance of the
studies?

--
View this message in context: http://r.789695.n4.nabble.com/How-to-use-
tapply-with-more-than-one-variables-grouped-tp4646948.html
Sent from the R help mailing list archive at Nabble.com.